如何在mogoose中嵌套填充中选择特定字段

Question

这是我的架构:

var UserSchema = new Schema({
    email: String,
    name: String,
    city: String,
    username: String,
    profilePic: String,
    phoneNo: Number,
    shortList: {
        project: [{ type: Schema.ObjectId, ref: "Project" }],
        flat: [{ type: Schema.ObjectId, ref: "Flat" }],
    },

});

var FlatSchema = new Schema({
    project: { type: Schema.ObjectId, ref: "Project" },
    status: String,
    floor: Number,
    size: String,
    type: String,
    flat_number: String,
    price: Number,
    flooringType: String,
    createdAt: { type: Date, 'default': Date.now },
    isDeleted: { type: Boolean, 'default': false },
   });

var ProjectSchema = new Schema({
    name: String,
    shortName: String, 
    developer: { type: Schema.ObjectId, ref: "Developer" },
    address: {
        street_address: String,
        city: String,
        state: String,
        pin: Number,
        position: {
            lat: Number,
            long: Number
        }
    },
    ofcAddress: {
        street_address: String,
        city: String,
        state: String,
        pin: Number,
    },

    overview: {
        size: String,
        area: String,
        configuration: String,
        possession_starts: Date,
        info: String,
        aminities: [{ type: Schema.ObjectId, ref: "Amenity" }]
    },
    images: {
        hdpi: String,
        xhdpi: String,
        web: String,
        mdpi: String
    },

});

这里用户链接与平面模型shortList.flat和平面模型是项目的链接

现在我想尝试选择所有细节如下:

User.findById(req.params.id)
        .populate('shortList.project', { 'CalculationsRules': 0, 'KBFlatTypeCharges': 0, 'CategoryPremia': 0, 'Floor': 0, 'KBUnitType': 0, 'floorplans': 0, 'flats': 0, 'towers': 0, 'galaryImages': 0 })
        .populate('shortList.flat', { 'pricedetails': 0 })
        .exec((err, user) => {
            if (err) { return handleError(res, err); }
            if (!user) { return res.json(401); }
//here i want to select specific field from project model
            User.populate(user, { path: 'shortList.flat.project', model: 'Project' },  (err, user) => {
                res.status(200).json(user);
            })
        });

它的工作正常但我想从名称和图像中选择一些特定的字段来形成项目模型

Answer 1

在填充中使用select属性:

User.populate(user, { path: 'shortList.flat.project', model: 'Project', select: 'name' })

这将只为您提供项目名称.

要指定您不想要的指定字段,您可以将其归零:

User.populate(user, { path: 'shortList.flat.project', model: 'Project', select: { 'name': 0, 'Floor': 0, 'flats': 0, 'towers': 0,} }

这适合我.

如果你正在做两个级别的人口:

我们可以简单地做到:

populate('project.tower', 'name project flats');

对于一个简单的填充来获取特定的字段:

populate('project', 'name')

Answer 2

尝试这样做：

applicantListToExport: function (query, callback) {
  this
    .find(query).select({'advtId': 0})
    .populate({
      path: 'influId',
      model: 'influencer',
      select: { '_id': 1,'user':1},
      populate: {
       path: 'userid',
       model: 'User'
      }
    })
    .populate('campaignId',{'campaignTitle':1})
    .exec(callback);
  }